A break-down of an actual math formula you can use to calculate the price for commissions and/or original pieces of artwork. Courtesy of AristDaily.com. It’s a good idea to have your price list figured out ahead-of-time and in a format ready to send through e-mail to prospective clients. I have a sheet of two (or more) samples of work — showing different levels of detail — and price points that correspond (ready to shoot over to clients when they show an interest). You might need to make separate sheets if you work in different mediums (watercolor, oils, etc.), as each medium takes different amounts of time.